As with any OTC medicine, stick to the manufacturer's dosage guidelines. Be aware that taking more than recommended (overdosing) on a combination of guaifenesin, diphenhydramine (the active ...

Guaifenesin, or glyceryl guaiacolate ... Take expectorants with a full glass of water. The dose and frequency of the expectorant depend on your age and health conditions. So, it's important ...